In the brain of Alzheimer's patient, the peptide composed of about 40 amino acid residue as is called amyloid β protein, that accumulates to form insoluble specks (senile specks) outside nerve cells is widely observed. It is concerned that this senile specks kill nerve cells to cause Alzheimer's disease, so the therapeutic agents for Alzheimer's disease, such as decomposition agents of amyloid β protein and amyloid vaccine, are under investigation.
Secretase is an enzyme which cleaves a protein called amyloid β precursor protein (APP) in cell and produces amyloid β protein. The enzyme which controls the production of N terminus of amyloid β protein is called as β-secretase (beta-site APP-cleaving enzyme 1, BACK-1). It is thought that inhibition of this enzyme leads to reduction of producing amyloid β protein and that the therapeutic agent for Alzheimer's disease will be created due to the inhibition.
Patent Literature 1 describes the compounds which are similar to those of the present invention, and the compounds have NO synthase enzyme inhibitory activity and are useful for dementia.
Patent Literatures 2 to 5 and Non-patent Literatures 1 and 2 describe the compounds which are similar to those of the present invention, and are useful for hypertensive agent, morphine like analgesic, tranquilizers, intermediate for medicament, NPYY5 antagonist, analgesic, or the like, respectively.
Patent Literature 6 to 24 are known as β serectase inhibitor, however, all compounds in these literatures have different structures from the present invention.